SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36d5ba9c25338fb176c1689bfd13e159663502bd69b8cd6b48407a6378d92172' 
  AND token = 'HUtu2BGYxOxjpk5+w73WJzmmasyesJwnXBKgObLrcMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}